Simple transaction rollback of Pymsql

Original link: http://www.cnblogs.com/HapyyHao1314/p/7384436.html

# coding:utf-8
import pymysql

class TransferMoney(object):

    def __init__(self,conn):
        self.conn=conn

    def check_acct_available(self,acctid):
        cursor = self.conn.cursor()
        try:
            sql = "SELECT * FROM test_rowback WHERE =%s" % acctid
            cursor.execute(sql)
            rs = cursor.fetchall ()
             IF len (rs) = 1! :
                 The raise Exception ( " Sorry,% s account does not exist, please check the information you entered is incorrect when " % acctid)
         a finally :
            cursor.close()

    def has_enough_money(self,acctid, money):
        cursor = self.conn.cursor()
        try:
            sql = "SELECT * FROM test_rowback WHERE id=%s and user_money>=%s" % (acctid,money)
            cursor.execute(sql)
            rs = cursor.fetchall ()
             IF len (rs) = 1! :
                 The raise Exception ( " due to lack of money leads to% s Account Transfer Failed " % acctid)
         a finally :
            cursor.close()

    def reduce_money(self,acctid, money):
        cursor = self.conn.cursor()
        try:
            sql = "UPDATE test_rowback SET user_money=user_money-%s WHERE id=%s" % (money,acctid)
            cursor.execute(sql)
            IF cursor.rowcount = 1! :
                 The raise Exception ( " Account Transfer Failed% s " % acctid)
             the else :
                 Print ( " transfer success " )
         a finally :
            cursor.close()

    def add_money(self,acctid, money):
        cursor = self.conn.cursor()
        try:
            sql = 'UPDATE test_rowback SET user_money=user_money+%s WHERE id=%s' % (money, acctid)
            cursor.execute(sql)
            IF cursor.rowcount = 1! :
                 The raise Exception ( " Accounts receivable failed% s " % acctid)
             the else :
                 Print ( " receivables success " )
         a finally :
            cursor.close()

    def transfer(self,source_acctid,target_acctid,money):
        try:
            self.check_acct_available(source_acctid)
            self.check_acct_available(target_acctid)
            self.has_enough_money(source_acctid, money)
            self.reduce_money(source_acctid, money)
            self.add_money(target_acctid, money)
            self.conn.commit()
        except Exception as e:
            self.conn.rollback()
            raise and


if __name__=="__main__":
    give_accid=1
    accept_accid=2
    money=100

    conn=pymysql.connect(
        host='127.0.0.1',
        port=3306,
        user='root',
        passwd='root',
        db='Python_test',
        charset='utf8'
    )

tr_money=TransferMoney(conn)

try:
    tr_money.transfer(give_accid, accept_accid, money)
except Exception as e:
    print(e)
finally:
    conn.close()

Create a database statement

CREATE TABLE test_rowback(
    id INT,
    user_name VARCHAR(1000),
    user_passwd VARCHAR(1000),
    user_money INT    
)ENGINE =INNODB DEFAULT CHARSET = utf8;

Note: When you create a database, you must add this sentence ENGINE = INNODB DEFAULT CHARSET = utf8;

 

Reproduced in: https: //www.cnblogs.com/HapyyHao1314/p/7384436.html